


Lead The Way

by Omoni



Series: Random Undertale Stories and Drabbles [1]
Category: Undertale (Video Game)
Genre: Alphyne, Alphys/Undyne-centric, Collar play, F/F, Gay Sex, I don't know, I still don't know, Leash Play, Lewff, Literal fucking nerds, Lots of Sex, Nerds in Love, Seriously there is a lot of sex, Smut, vanilla bondage
Language: English
Status: Completed
Published: 2016-05-16
Updated: 2017-08-14
Packaged: 2018-06-08 20:34:19
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 8,481
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6872431
Author URL: https://archiveofourown.org/users/Omoni/pseuds/Omoni
Summary: <blockquote class="userstuff">
              <p>Some plot-what-plot lewff involving a dumb human cult movie, a collar, and Alphys and Undyne. </p><p>Yes, this means smut. What did you expect? And no, I have no idea. I just wrote it for fun - and to see if I could. I don't expect anyone to read this, either o_o.</p>
            </blockquote>





	1. Collared

One night, Alphys surprised Undyne, whom in turn surprised her.

They had both been signaling to each other for most of the night the desire for sex, and Alphys had a specific reason why, one she'd managed to keep a secret from Undyne for an entire week. It was a Friday night - also part of her plan. as she knew, if she were successful, they'd both need a day to recover - when she finally brought it up.

She'd been bored one day during a lunch break when an absurd idea came over her, one she remembered bringing up with Undyne only once, after a lot of blushing and fogged glasses, only to be laughed off.

They'd gone to see a ridiculous human cult movie with Mettaton, Papyrus, and sans (Mettaton's idea, Papyrus's future nightmare fuel, and sans's boredom cure - so he'd hoped) and had sat snickering through all of it while Mettaton fumed, Papyrus covered his eyes, and sans surfed UnderNet, bored.

However, one thing alone Alphys actually found intriguing, and when they were alone, she'd asked Undyne, blushing, "Some of it... the non-stupid stuff... was kinda... i-interesting, huh?"

Undyne blushed in return, blinking. "Uh," she muttered, scratching at her cheek "Like what?"

"Er," Alphys looked down, her glasses fogging up. "The-the... the..." She gestured around her neck, before adding, "Nevermind!"

Undyne, however, was scarlet, staring at her wife with a new eye. "Me, too!" she admitted.

Alphys looked up at her in shock, then they both laughed to tears.

Nothing came of it then, but Alphys never forgot.

So that bored lunch hour she surfed the selections, found one she knew would fit both of them (in case she was wrong. [She was.]), and ordered it without a second thought. She kept it barely a secret for the entire week, and now, finally, she could share it.

"So, uhm..." Alphys shifted a little, bright red, as Undyne was reaching back to unhook her bra.

"Mm?" Undyne murmured against her shoulder, and Alphys shivered, unable to help it.

"I-I have a surprise for... for us... for tonight... uh." She shut up when Undyne leaned back to face her, having successfully unhooked aforementioned bra and was now interested in this surprise.

"Oh? What kind?" Undyne was grinning. Any time Alphys had a surprise to show her in bed, it was usually a kind of outfit that always got Undyne hot and bothered, and she delighted in removing those outfits very, very slowly.

Alphys bit her lip, looked away, and smiled shyly. "Er... just... close your eye!"

Undyne did, and Alphys both shrugged off her bra and reached to her nightstand and grabbing a small, shiny clothed bag. She held it in both hands, shaking from both anticipation and nervousness.

"Here," she said, holding it out to Undyne, who opened her eye and took it, bemused.

"I, uh, figured you'd want me to wear it..." Alphys was saying, as Undyne slowly opened the bag and looked inside, her blood igniting the moment her brain processed what it was. "B-because you're so s-strong and..."

Undyne already had pulled it out and was buckling it around her own neck, her face pink and her smile huge. It fit perfectly; a collar made of imitation leather, dark green, with a generous clasp dangling from the front big enough for a lead or a finger or two to grab onto.

The moment it was secured in place, Undyne shut her eye, threaded a finger through the clasp, and actually shuddered, sighing deeply.

"Okay..." Alphys said weakly, her own body feeling hot, now. "Not what I was expecting at all." She was unable to look away, the look of pleasure on Undyne's face not one she'd ever seen before - but suddenly realised she liked it very much.

"I think I really like this," Undyne breathed out, sitting up and kneeling in front of Alphys. "I didn't know you knew, Alphy. _I_ didn't even know until I saw that stupid movie!"

"I... Same here," Alphys agreed. "But I thought... you'd want t-to be... you'd want me to wear it..." She pointed to her own neck, and Undyne blinked in surprised. "B-because you're a-already so in c-control..."

"No way!" Undyne grinned. "Alphy, I want to be _yours._ I want to follow you. Most of all... most of all..."

She looked away, her smile crooked. "I want to _please you." S_ he looked back and licked her lips, and Alphys swallowed, hard.

"So, Alphy," Undyne said, her eye dark, now. "Tell me what you want me to do."

Those words had quite an effect on Alphys, who had never before known this side to herself until she heard her wife utter that one, simple sentence. She'd always thought of herself as the weak one, the perfect bottom and never one to take control very often.

Therefore, when suddenly - and literally - faced with Undyne demanding her to order her around sexually... it definitely effected her quite deeply.

"Don't get a nosebleed," Undyne grinned, and Alphys blushed, actually worried that that would happen.

Undyne laughed and leaned on her, looking up at her with a sparkling eye, and Alphys sighed. "You know I wouldn't be able to help it if I had!"

"I do, Mistress," Undyne replied with a grin.

Alphys's eyes flared, her whole body flashing hot again at that. She had had no idea she had this side to herself, but apparently either Undyne did, or was just incredibly lucky at guessing (it was the former). "D-did you just...?"

"Yes, Mistress," Undyne grinned up at her, sliding her arms around Alphys's waist.

Alphys stared at her, barely able to think, now.

Well, maybe not completely. "S-so, what I-I want, you'll... you'll d-do?"

Undyne nodded. "Yes, Mistress. Well, I'll tell you if I don't want to," she admitted, and Alphys nodded in agreement, glad for that. "But I don't think that'll be an issue..."

She leaned close and whispered, "Right, Mistress?"

Alphys stared at her, then reached forward and pulled her close, one hand going to Undyne's cheek, the other hooking a claw around the clasp of the collar and pulling her closer, kissing her deeply. Undyne's eye closed, her arms tightening around Alphys's waist, a small sound coming from her throat when she was pulled close.

Against her lips, Alphys said, her voice sharp, "Get naked."

Undyne pulled away slowly, nodding and sitting up to push down her shorts and underwear together, her eye still on Alphys with every move.

"Okay," Alphys said in that same tone. "Now, me."

Undyne came back and reached down, undoing the button and zipper of Alphys's jeans and pulling them down, Alphys balancing to make it easier, her hands caressing Alphys's legs and thighs as she slid them down. Once the jeans were tossed aside, she did the same with Alphys's underwear, leaning down and tailing her lips down her legs this time. Alphys lay back, unable to keep her balance at this, overwhelmed, and Undyne smiled at her.

Then, Undyne pulled away and sat down on her knees again, her eye shining. "Now what, Mistress?" she asked, slightly breathless.

Alphys sat up and kissed her, throwing her arms around Undyne's neck and pulling her down onto the bed with her.

"Kiss me," Alphys ordered, her voice getting stronger, "all the way down."

She was amazed by her own boldness, but oddly she found it was very arousing, especially when Undyne grinned and licked her lips again.

"You've got it, Mistress," she purred, leaning down to lick slowly from Alphys's lips to to her neck, biting lightly, and Alphys shut her eyes, reaching out and grabbing onto Undyne's shoulders. She kept her hold until Undyne dipped down to her chest, and her hands grabbed onto the bed instead, as now Undyne licked slowly along first one, then the other, nipple of each breast. Her attention was slow and careful, and Alphys squirmed a bit, unable to help it.

Undyne trailed her tongue slowly along Alphys's ribcage, then belly, then lower, until finally she was nestled between Alphys's legs, looking up at her with a grin and a red face.

Alphys looked down, and Undyne said, "Now what, Mistress?"

Alphys stared at her, and she could see the glow of teasing deep in her eye; she knew what was 'now what', but fully intended to play it for what it was worth.

"Undyne...!" Alphys said, unable to keep the slight whine from her voice. "Please, please, _please_ keep going!"

In reply, Undyne lay down on her front, propped herself up on her elbows, and leaned down, kissing along the inside of one of Alphys's thighs slowly. Alphys sighed, relaxing and closing her eyes, only to shift when Undyne's tongue finally licked along her centre, lingering ever-so-slighting over her clit before diving between to lick directly to her core. Alphys breathed out a small moan in reply.

Undyne _loved_ to go down on Alphys. There was something almost intoxicating about the way she tasted and the way she reacted when tasted that drove Undyne crazy at times.

Alphys reached down and sought one of her hands, which she offered, and Alphys held it tight, her other hand, Undyne saw, at her chest and over one of her own breasts. _That_ also had a profound effect on Undyne, as seeing her wife so aroused that she got lost in it was one of her biggest turn-ons.

With another purr, she closed her eye and licked deeper, flicking the tip of her tongue occasionally over Alphys's clit - which in turn had Alphys's claws digging into Undyne's hand, deeper with each lick.

"Undyne," Alphys whispered, her eyes opening slowly. "Use your fingers... too..."

Undyne opened her eye, looked up at her, seeing that she was now staring back, her eyes glazed over and face red.

Undyne nodded, bringing her free hand down to slowly stroke already wet and hot flesh, before pushing two deep, her tongue now focusing on her clit. Alphys shut her eyes again tight, heat and pleasure lancing through her each time Undyne's fingers pushed deep.

Undyne loved watching her, her own breaths quick and her heart quicker. Alphys rarely lost control, so when she did, it was quite wonderful to see.

When Undyne crooked her fingers up slightly and rubbed gently within Alphys, her wife cried out, a sound Undyne adored, so much that she could feel her own arousal grow. Closing her eye again, she focused on those sounds, pulling her other hand away in order to grab hold of Alphys's hip to keep her as in place as possible.

Alphys was squirming now, one hand over her mouth and trying to muffle already loud sounds, her other hand digging into the bed beneath her.

Undyne wanted her to lose that last bit of control, to hear her voice unmuffled, so she increased the speed of her fingers and flicked her tongue over her clit even closer.

Alphys was gasping now, barely able to see, let alone breathe. She was _so_ close, everything Undyne doing so incredible and in _just_ the right ways...

When Undyne's fingers suddenly pressed down deep inside her, Alphys lost it, and she groaned out Undyne's name desperately, both hands clutching at the mattress, arching her back and throwing her head back as she came - and came _hard_.

It was incredible, how amazing this climax felt, and Undyne worked to making it feel as best as she could.

"Breathe, please, Mistress," Undyne said sharply, jerking her head up in sudden alarm, and Alphys did, gasping for air. It was so easy to forget to breathe when one felt like a wispy cloud of pleasure about to float away...

Undyne slowly pulled her fingers free, licking them off with a small sigh, closing her eye in pleasure. Alphys lay there, her hands loosely holding the blanket beneath her, her eyes shut and her breath raspy.

Undyne crawled slowly up the length of her side, then curled up against Alphys and whispered, "Was that nice, Mistress Alphy?"

 _"Oh,"_ Alphys burst out, "A-am- _amazing!"_

But then she surprised Undyne - no small feat, that - by opening her eyes and staring at her. _"We're not done,"_ she suddenly said, her voice stronger.

Undyne blinked, actually bemused by this, but Alphys sat up and reached for her, hooking her by the collar again and pulling her into a deep, blood-igniting kiss. Undyne whimpered against Alphys's lips, still rather turned on by her own actions as well as he wife's, and Alphys responded by licking her lips apart and kissing her harder.

Quite suddenly Undyne found herself pinned down, and Alphys pressed closer, so close she could feel Alphys's heart racing against her own.

Alphys reached down and slipped her hand between Undyne's legs, fingers reaching up and deep, and Undyne shifted against her touch, her eye closing. She reached up and wrapped her arms around Alphys, who in turn kissed her deeper, and again Undyne whimpered.

 _"Alphy,"_ she whispered against Alphys's lips, and in reply, Alphys pressed down and pulled her hand away to shift herself between her legs. She reached up and pulled Undyne's arms away from around her, holding her by the wrists and pinning them above her head. Undyne's eye closed and she sighed deeply, then shifted when Alphys's knee went between her legs. Undyne hooked her legs around Alphys's leg and murmured desperately.

 _"Please,_ Mistress," she begged brokenly, and Alphys nodded, leaning down and licking Undyne's neck slowly.

Alphys pushed close, and Undyne shifted against her, matching her move for move, Alphys starting slow, wanting it to last. Undyne, however, felt already half-crazy with need, and instead pushed up against her with a moan, trying to urge Alphys to move faster. Alphys could never resist Undyne when she was like this, so she obliged.

This time, Undyne was the one crying out, her hands clenched as Alphys kept them pinned above her head. They kissed again, and Undyne arched up, the sound of Alphys's name strangled as she broke from their kiss to say it.

Alphys knew what that meant and held her down as she came, her eye shut tight and her teeth bared, her breath catching just a bit.

Alphys let go of one of Undyne's wrists to stroke the hair away from her face slowly, as Undyne went limp beneath her, her own body following suit.

With a shudder, Alphys relaxed, resting her head on Undyne's shoulder, her hold on Undyne's other wrist going slack. She closed her eyes, slipping her hand down from Undyne's hair to her neck, tracing the collar slowly before hooking her claw through it again.

Undyne swallowed hard hard, whispering, "No more yet, please, Mistress..."

Alphys smiled. "I agree," she admitted, keeping her eyes shut. "Undyne, that was... that was..."

"Hot?" Undyne offered with a grin.

"Yes. And incredible. We've never had sex like that before."

"Your fault," Undyne said tiredly. "You bought the thing."

"Yes, but you wearing it..." Alphys snuggled closer. "I wasn't expecting that."

"Your reactions..." Undyne replied. "I knew you had it in you."

"I didn't," Alphys admitted, blinking at the memory of her bossing Undyne around - _Undyne_ , of all people, and in this context, too. "But you're right. Something about you... about your wanting me... I-I liked it."

Undyne opened her eye and gazed up at her. "I _loved_ it."

"So I guess that movie wasn't complete garbage," Alphys concluded.

"No, it was, but it had at least one good idea." Undyne paused. "Don't tell Mettaton. We'd never live it down."

Alphys laughed. It was true, after all.


	2. Leashed

"Hey, Alphy."

"Yup," Alphys said shortly, her eyes glued to the screen in front of her, her thumbs flying over the buttons.

"I think I'm gonna try something new for tonight."

"Oh?" Alphys replied, still distracted. She tried to listen, but was so close to getting past this one mini-boss...

"Yeah. So, I'm gonna go do that, slip into something more... naked. If you're up for it, I'll be in bed."

"Alright," Alphys answered automatically.

Undyne grinned, glad that she'd guessed right. Silently, she slipped to their bedroom and got undressed quickly - before she reached under the bed, pulled out a box, and put something else on - or rather, two things. Then, she sat down and waited.

Alphys blinked suddenly, her face going bright red before her thoughts caught up with her. Once they did, her character was immediately killed, but she didn't even see it. She squeaked, threw threw console aside, and scrambled to her feet, her heart racing. Undyne's words had finally soaked through, and she was suddenly brainless.

She stumbled into the bedroom - and froze, her eyes going wide and her whole body flooding hot.

Undyne lay on the bed, partially sitting up and resting on her elbows, her legs crossed and out before her. Her expression was one of triumph, and in one hand, she idly twirled the end of something.

Alphys's eyes followed it, and suddenly realised what it was - and she almost fainted.

It was the handle a leash, a leash that was attached to the collar around Undyne's neck - the only thing she was wearing.

"Hey," Undyne greeted her, her voice wavering a little, both from trying not to laugh - but also trying to stay calm, as Alphys's reaction to her was honestly rather flattering - and arousing. "Up for some fun tonight, Mistress?"

Alphys was already rushing to the bed, and she landed on it with a bounce, grabbing Undyne's face between her hands and kissing her, hard. Undyne made a soft sound of surprise, but returned with equal fervour, suddenly realising that Alphys was just as hungry as she.

Alphys's hand trailed down Undyne's arm and closed over the hand that held the leash, not breaking this kiss, her other hand moving down lower. Undyne let go of the leash, and Alphys twisted it around her hand, tugging on it a little. Undyne made a soft sound against her lips, her eye fluttering a little; the feel of being tugged closer that way sent a spike of sharp lust into her, and her heart suddenly sped up in anticipation.

"Undress me," Alphys murmured, tugging again on the leash, only this time harder.

She kept her eyes open, watching the effects of her actions upon Undyne's red face. She felt Undyne reach up and tangle her hands in Alphys's shirt for a moment, and Alphys pulled away to make it easier for her. The moment she let go of the leash, her shirt and bra were off and over her head, bumping her glasses askew, and she grinned.

When Undyne was eager, she was clumsy, and very little was as arousing to Alphys as that. Once she grabbed hold of the leash again and tugged gently, Undyne blushed deeper and bit down hard on her bottom lip, a small purr escaping her.

Alphys sat up, and Undyne moved as close as possible, pressing herself right against Alphys, and they both sighed deeply, embracing for a moment.

"God," Undyne whispered, her voice strained. "Oh, god, you're _so hot,_ Mistress."

Alphys went scarlet, and she felt that blush spread. She never understood it, but whenever Undyne called her that, she felt amazing - both sexy and confident. She never felt this good at any other time, though often after, it would stay with her for a few days. To have someone like Undyne eager and desperate for someone like her always amazed her - not to mention the trust Undyne showed, too.

Undyne slowly moved her hands down Alphys's sides, making her shiver with delight, and in reply to this, Undyne started kissing her neck. Alphys clung to her, burying her face into her shoulder, her claws digging into her back. The feel of that sent Undyne into an even bigger haze, and suddenly she was scrabbling at Alphys's pants, tugging them down and off so quickly she accidentally ripped them a little. Alphys, however, barely noticed or cared, especially when Undyne pulled her underwear off similarly.

For a moment, Undyne touched her, trailing her hands over Alphys's body slowly, her eye closed and her smile wide. She loved how Alphys felt, loved how her skin felt beneath her fingers. She traced the myriad scars of stretch marks and sighed, feeling so lucky in that moment - a feeling that increased when Alphys whispered her name and pushed closer.

"Yes, Mistress?" she replied gently, saying it against her shoulder.

Alphys leaned back, her eyes half-closed and dark with desire. "Lie down," she replied, her voice husky.

Undyne grinned and lay back down on her back, and Alphys grinned in return. She had a daring idea, and it made her feel both very shy but also very eager for it. She straddled Undyne for a moment, something that had her wife moan and reach up to grab hold of her forearms.

But then, Alphys slid up more, and Undyne opened her eye, a sudden jolt hitting her, hoping that what she thought was going to happen was happening, now.

She was right; Alphys moved right up to her face, before hesitating, looking down at Undyne for a moment. When Undyne reached up and grabbed hold of her backside, digging her fingers in, and Alphys relaxed.

"Please, Mistress," Undyne murmured, licking her lips. "Let me taste you."

"Yes," Alphys replied, lowering herself down. She propped herself up by holding onto the headboard, but as soon as she did, Undyne made a low sound of pure want and licked along her slit slowly.

Alphys tilted her head back and gasped, her eyes closing - but not before she tugged again on the leash.

Undyne squirmed at that, especially since it brought her even closer, and she shut her eye, sliding the tip of her tongue slowly between Alphys's folds, the taste maddening to her. Her legs bent up at the knees, trembling, and she dug her heels into the bed. When she felt Alphys relax even more, her thighs gently pressing against Undyne's cheeks, Undyne was officially lost to her. She buried her face between those thighs and licked deeper, finally getting to taste her, and she felt drunk on it immediately.

Alphys was in a similar state, and her tail curled up, the feel of Undyne's tongue deep within her one of the best feelings in the world. She felt her body respond, and carefully, she started to move against Undyne's face, unable to help it.

Undyne was delirious, now. She slipped her tongue up and trailed it along Alphys's clit, pressing down before flicking her tongue against the nub. Alphys cried out, her claws digging into the headboard, and Undyne purred again, wanting to hear so much more.

She increased the pace of her tongue, focusing mostly on Alphys's clit, but also occasionally dipping it down into her centre, savouring every single thing: the feel of her firm, slick skin, the way she tasted, the way her clit seemed to always find her tongue, instead of the other way around...

"Faster," Alphys suddenly grunted out, lowering her head and gasping.

Undyne complied, and she moaned, a long, soft sound that sent Undyne's heart racing. She dug her fingers into Alphys's hips, urging her to move more, and suddenly, Alphys relaxed completely, abandoning herself to it all. The moment she did, she was rewarded, as everything grew even more intense.

She tugged on the leash again, a gesture accompanied by Undyne's name.

Then, surprising both herself and Undyne, she felt her hold snap, and she cried out, her body stiffening and grinding as her orgasm slipped through her and took her over, her claws leaving scratch marks into the headboard.

Undyne grabbed hold of her and held her close, licking deep and close in order to make it last. Alphys cried out again, her voice breaking, and in that moment, she leaned to the side and fell over, limp and spent and gasping for breath.

Undyne stayed where she was, licking her lips again and grinning. Beside her, Alphys trembled, calming down, and she turned to her side and looked at her.

It took longer for Alphys to open her eyes, but once she did, and once she saw Undyne staring at her with a hungry grin, she sat up and tugged on the leash, _hard_.

Undyne sat up, her eye glinting, and Alphys grabbed her and kissed her - _harder_. Undyne's eye rolled up and she clung to her wife, returning the kiss and deepening it.

"Undyne," Alphys whispered between kisses.

"Yes, Mistress?" she replied breathlessly.

"I want you to... I want you to..." Alphys stammered, not used to saying this.

Undyne opened her eye, and Alphys grinned, the grin almost feral - something that had Undyne's mouth go dry.

"What would you like me to do, Mistress?" she asked, her voice wavering in anticipation.

Alphys pulled on the leash, so hard that Undyne stumbled a little, and she moved atop of Alphys. When her eyes glazed over in response to that, Undyne grinned.

 _"Undyne,"_ she growled out, her free hand going down and grabbing onto her backside, so hard that Undyne felt claw. _"Fuck me."_

Two words. Only two words, but it broke something in Undyne. Alphys rarely ever said the word fuck on its own, and never in this context, before. To hear her say it, while holding that leash and tugging on it, drove Undyne to the point of wildness, and in seconds, she had Alphys pinned beneath her, had straddled upon her, and was now pressed fully against her body. Alphys closed her eyes, her face reddening, yet she grinned and held her tight, tugging yet again. Undyne reached down with one hand to make sure they were close enough, before she pushed down. Their flesh met, and Undyne shifted a little to bring their clits closer together.

The moment that happened, Alphys made a sound, one choked with longing, and Undyne pressed down flat against her, holding her face between her hands. They kissed, and Undyne started to move.

However, she didn't start slow like usual; instead, she started fast and hard, something that had Alphys reeling and clinging to her, another moan escaping her.

Undyne grinned, breaking from their kiss for a moment to simply _look_ at Alphys, and she was spellbound. Alphys's eyes were closed tight, and her face was scarlet, but she was smiling, so brightly and with such abandon that Undyne's heart clenched.

"Yes," Alphys murmured, her voice like music to Undyne. She buried her face into Alphys's neck, kissing there gently, and Alphys arched up against her, gasping. "Yes, _yes!"_

She couldn't help it; Undyne was moving perfectly against her, every shift of her hips sending a bite of aftershock through her, and already, it was building up, again.

"Is this good, Mistress?" Undyne wondered, before gently biting the curve of Alphys's neck.

Alphys squirmed and nodded, her only response another cry, and Undyne felt a thrill go through her. From that, alone, Undyne could feel herself getting close.

"Come for me," Alphys suddenly commanded, her voice sharp and clear. "Undyne - _yes - ah_ \- please, _come for me!"_

"I will, Mistress," Undyne answered, barely getting it out between her teeth. "I-I'm... close."

 _"Good,"_ Alphys growled. She twisted the leash around her hand tighter and gave it a yank, and Undyne was the one squirming, now, her head now raised and tilted back, her breaths short and raspy. When Alphys noticed, she did it again, and Undyne cried out, increasing the pace and digging her nails into Alphys's shoulders.

"Alphy..." Undyne murmured, feeling the pull of pleasure starting. She tried to hold off, hoping that Alphys would pull harder or command her more, but she couldn't - it felt too good to resist.

 _"Alphy...!"_ She _shrieked_ it out, her eye squeezing shut, and she came, hard, crying out and staggering above Alphys, who held her tight and moved with her.

When she could, she relaxed, feeling those waves of pleasure move through her body like a gentle tide. She made a soft sound, between a sob and a moan, and Alphys kissed her, something she returned.

When she did, she felt another tug, and she opened her eye to find Alphys staring up at her, her eyes glazed with lust.

"More," she growled against her lips, shifting her hips up and rubbing against Undyne, something that had her purring and moving closer from.

 _"More,_ Undyne," Alphys repeated, an edge in her voice, and she tugged harder.

Undyne grinned, adjusted herself a little, and started to move again, resuming that fast pace. They both cried out immediately, clinging onto each other for dear life - and with thrilled happiness.

"Make me come again, Undyne," Alphys whispered, burying her hot face into Undyne's shoulder. "Please... _please_?"

"Yes, Mistress," Undyne gasped out. "But... _I_ might... I feel like I..."

Alphys opened her eyes, feeling a thrill of her own, now. "Yes," she agreed. _"Yes!_ Come with me, feel it with me, _fuck me, Undyne!"_

"Oh, god, _yes,_ Mistress," Undyne agreed, her voice hoarse. _"Yes...! Alphy...!"_

From there, it didn't take long for either of them. The pace was too fast, and both were already so sensitive and high, that it was impossible to hold off for much longer.

Alphys felt it, first, her whole body clinging onto Undyne tight - even her tail, around one of Undyne's shins - and she cried out her wife's name, not once, but countless times.

That alone would have been enough for Undyne, but Alphys took it a step further, and she pulled on the leash _hard_ , so hard that there wasn't even air between them, now - and Undyne felt herself tumbling after her.

They writhed together, lost completely in their shared pleasure, and that moment seemed like an eternity - one filled with pure, undiluted bliss.

When it faded, it was so gradual that they barely noticed. Undyne relaxed heavily against Alphys, who held her close and started stroking her hair slowly. They both gasped for breath, trembling - but they were both grinning.

"Holy _shit,"_ Alphys whispered suddenly, surprising Undyne into laughing and kissing her cheeks several times until she, too, started to laugh.

"You're a good mistress, Alphy," Undyne teased when they calmed, poking her nose affectionately.

"Undyne, _holy shit,"_ was her answer.

Then, she added, her voice sly, "What _else_ do you have in mind, I wonder?"

Undyne blushed; she actually had one more thing she wanted to try, but she wanted it to stay a surprise.

So she said, "I dunno..."

Alphys smirked. "You're lying. You still have the collar on. I _could_ command you to tell me."

Undyne laughed. "Oh? Aren't there better things to command of me?"

Alphys was quiet for a moment, and Undyne looked up at her, noticing that she was not only blushing - but it was increasing.

Their eyes met.

Then they both grinned at each other.

And then, Alphys's eyes gleamed, and she gave the leash a tug.

They didn't leave the bed for the rest of the night after that.


	3. Bound

Sometimes, Undyne felt as though she were addicted to Alphys.

It was always something small, be it a shy smile when she was kissed, or the glint of triumph when she won a game, or even times when she got so angry over something so silly that she just stood and ranted, with her whole body. Undyne often found herself wanting Alphys, probably at the most inappropriate of times, but she couldn't help herself, really.

An example: they'd just finished watching a romance movie (one with two women, and a romantic comedy at that - very rare in human media), and Alphys started crying, her face red and her smile huge upon her face, her eyes shining.

Undyne found herself staring at her, her teeth sinking into her bottom lip.

"That was so _beautiful,"_ Alphys murmured, brushing her tears away and placing a hand over her heart. "Th-that was _so beautiful!_ I _loved_ it!"

"Me, too," Undyne replied, her voice low, trying to keep a waver from her words.

Alphys leaned back and closed her eyes, still smiling. Her tail thumped happily on the couch. "I wish there were more like that," she admitted. "I know _our_ media is like that, but human media is so bereft of it, so to see it... Uh-uhm, Undyne?"

Undyne had suddenly moved closer and, without a word, sat down upon Alphys's lap, sliding her arms around her neck and her legs tight around her waist. Alphys opened her eyes, finding Undyne already staring at her with both a blush and a wide, teeth-baring grin.

"Hi," Alphys whispered, her arms going around Undyne's waist.

Undyne moved closer, her heart stuttering at that. Alphys's expression was so cute - one of surprise and wonder - as was the single, bemused word she uttered.

 _She's so damned adorable,_ Undyne thought, immediately tongue-tied.  _As if I'm a present she's so happy to receive, every time..._

Alphys smiled up at her, and Undyne couldn't hold back anymore, not when she was looked at like _that_. She pushed close and kissed her, deeply, and Alphys immediately returned it, her claws digging into her back a little.

They kissed, moving as close as possible and clinging to each other, hands moving over curves and fingers digging in with eagerness they now both shared. It made them both dizzy and giddy, feelings they both loved, and soon, Undyne started pulling at Alphys's clothes.

"Alphy," Undyne whispered against her lips, "I want you, _badly."_

Alphys shivered, the sound of Undyne's voice so arousing that she couldn't speak. She nodded, instead, kissing her again, but Undyne pulled away, and she made a sound of protest.

"Bedroom," Undyne whispered, her eye dancing. "I have a _great_ idea."

Alphys blushed, suddenly very intrigued, and she nodded.

Undyne moved off of her and got to her feet, and Alphys did the same - only to immediately find herself back in Undyne's arms. They kissed again, and Undyne carried her to their bedroom.

For a while, they spent the most time undressing, taking their time to enjoy each other's bodies with each piece of clothing removed. They took turns, Alphys sometimes on top of Undyne, then vice versa, before they were finally naked and clinging to each other. Both were almost desperate, now, panting and grinding against dampening flesh.

However, as soon as Alphys was about to move to bring them together, Undyne reached up and stopped her - though it took a great deal of self-control to do this, and she trembled.

Alphys opened her eyes, the bemusement back, but Undyne suddenly grinned, and she felt her heart skip.

Undyne pulled away, then reached over the side of the bed and beneath it, pulling out the box they both knew so well.

Alphys lit up, her tail wagging, again, and Undyne laughed. She handed the box to her, and Alphys took it, grabbing the collar and moving close to Undyne in order to put it on. She brushed her body over Undyne as she did, and Undyne was the one shivering, now.

Alphys reached for the leash, but instead, her hands fell on... rope?

She pulled it out, confused, but when she saw Undyne's grin turn almost feral, she suddenly understood. She blinked, surprised by her body's sudden reaction to this: a wave of pure heat, from head-to-toe.

"I'd like you to tie me up, please, Mistress," Undyne explained, her voice husky, now. Her heart raced, growing more and more excited by the concept.

Alphys hesitated. "A-are you sure? Th-this could hurt if I'm n-not careful..."

"Then I'll tell you," Undyne promised, gently taking the rope and looping it around the headboard from the back, so that each end of the rope was still accessible. She then held the ends out to Alphys, who took them with a sudden, slow smile.

Carefully, she tied the ends around Undyne's wrists, making sure they were secure but also loose enough for blood circulation. The moment she felt her arms go above her head, Undyne closed her eye, a stab of sudden lust hitting her core. She tugged on them, and while they gave a little, they were still tight enough to keep her in place.

She stared at Alphys, then, her eye wide and dark and her grin so wide her cheeks hurt.

Alphys sat for a moment, just to take it all in.

It was almost surreal, seeing Undyne like this: Undyne, the strongest warrior she knew, the bravest, the proudest and most confident, was suddenly a puddle before her, tied to their bed and loving every second of it.

Alphys felt her breathing get a little short, and suddenly, she lunged for her, crashing atop her and grabbing her face between her hands, kissing her so hard they both moaned from it.

Undyne found herself suddenly conflicted; she wanted to touch Alphys, but couldn't, and yet Alphys could touch her anywhere and everywhere. Giving Alphys that freedom - and trust - was not only arousing, but oddly humbling, too. She squirmed a little, tugging on her wrists, but she didn't try _too_ hard, really.

Alphys broke their kiss to instead lick down Undyne's neck and toward her breasts, her hands firmly on her hips. She sat on Undyne's thighs, unable to help rubbing a little against them, and Undyne felt that - and how wet she was - and closed her eye, tilting her head back.

Alphys then licked one of Undyne's nipples, and she purred, relaxing even more, though her hands twitched a little. Alphys circled her nipple with the tip of her tongue slowly, drawing out the sensations for her, and she smiled, licking her lips.

When Alphys moved to her other breast, one of her hands moved down and between her legs. Undyne spread them as best as she could, biting her lip, and Alphys slipped her fingers between her folds, trailing the tips slowly upwards until she reached her clit.

However, with a sudden smile, she held them still, hovering just over Undyne's clit, her tongue still working over her nipple.

"Ah..." Undyne gasped out, moving her hips and trying to get Alphys to touch her.

Suddenly, she felt Alphys sit down harder on her thighs, and she found herself unable to move.

"Mistress...!" she pleaded, her voice strained. She arched against the headboard, tugging harder with a frustrated groan, and she heard as well as felt Alphys laugh softly against her breast.

"What's wrong?" Alphys wondered, raising her head and looking at Undyne mischievously.

Undyne stared back, her face bright red and her mouth dry. Alphys kept her fingers still, though the moment their eyes met, she shifted her index finger up - just a little - and brushed it over that nub so quickly that Undyne cried out, her voice breaking.

"Mistress, _please!"_ she blurted out, arching again a little and trying to move her hips. "Please, touch me! _Please!"_

"Well," Alphys shrugged, grinning, still. "Since you asked so nicely..."

And she finally moved her fingers up and upon Undyne's clit, feeling it throbbing beneath them. Undyne gasped again, jolting from the feel of sudden pleasure hitting her.

"Thank you!" she cried, barely realising she said it. Her head tilted back again, and her eye closed tight. "Thank you, Mistress, that feels _so fucking good,_ please... _please_ keep going...! _Ah...!"_ The moment she asked, Alphys not only did so, but did at a fast pace, causing her to cry out.

Alphys shifted and moved off of her thighs, and Undyne immediately raised her legs and spread them, laughing in relief. Alphys pulled her hand away at that, shocking Undyne into jumping and sitting up again, her eye wide and her mouth open, speechless.

Alphys smirked, then moved between her legs. Before Undyne could even ask, Alphys had moved her head down and started licking slowly along her slit, and Undyne was suddenly encompassed in bliss.

Alphys took hold of Undyne's legs and hooked them on her shoulders, then grabbed her by the hips and pushed her tongue deep into her centre. Undyne cried out her name, loud, and moved with her, and Alphys felt herself light up, her own arousal blazing at the sight of Undyne's. She slid her tongue up to her clit again, then moved a hand down and drove two fingers into her centre - all starting and remaining at a fast pace.

Undyne was completely lost to her, now, the feeling of raw pleasure building up so quickly that she could barely breathe. She pulled hard against the restraints, feeling a jolt when they still held her, and she gritted her teeth, her heels digging into her wife's back and her body practically undulating with ever thrust of those fingers.

"M-Mistress," she rasped out, between her teeth. "A- _Alphy_...! _I'm_...!" She couldn't finish her words - but her body certainly could, in its own way. Alphys pulled her closer, her tail thumping happily on the bed, and she increased the pace, loving every second of this, too.

When Undyne came, two things happened: she _shrieked_ out Alphys's name, her voice high-pitched from the strength of her orgasm, and she pulled so hard on her restraints that, without warning, they _snapped_.

Undyne fell forward, gasping in shock, and Alphys sat up quickly to catch her, moving out from beneath her legs to do so. Undyne leaned against her weakly, gasping for breath and grinning, her hands now limp upon the bed.

Alphys held her, stroking her hair, as she calmed, trying _very_ hard _not_ to laugh at what had just happened.

Then, when Undyne was calmer, she murmured, "Oops."

Alphys burst into laughter, unable to hold it back at that, and she kissed Undyne all over her face, bringing tired laughter from her, too.

"Well," Undyne added, blushing. She clumsily untied the rope from her wrists, now annoyed. "That was short."

"Hm," Alphys replied, getting her attention. She looked up, tossing the ropes aside, and saw that was Alphys smiling slyly at her.

Then, Alphys raised a hand, her fingertips sparking, and suddenly, Undyne found herself pulled backwards and slammed into the headboard, her hands held up above her head tight. She let out a grunt of surprise, her eye wide, and she looked up to find her wrists fastened in place by bright yellow cuffs, ones that would spark occasionally but otherwise merely felt warm against her skin. She pulled on them as hard as she could, and to her surprise - and growing delight - they didn't budge one bit.

 _"Holy fucking shit,"_ she concluded, starting to grin, her heart speeding up as well.

Alphys smiled, looking very pleased with herself, indeed. Her tail thumped again happily, and, she met Undyne's gaze, licked her lips slowly. Undyne stared at her, feeling a wave of heat go through her so fast that she shivered.

"Mistress," Undyne murmured, pulling a little against the restraints, forgetting for a moment in a sudden urge to grab Alphys and kiss her. "Mistress, what do you plan to do?"

Alphys smiled at her, her eyebrows going up in thought as she chewed on her thumb's clawtip for a moment.

Undyne watched her, her arousal growing stronger the longer she did, and she saw keen calculation within Alphys's eyes, a kind that Undyne felt through her whole body - especially her centre.

"Well," Alphys said finally, lowering her hand and instead crawling over to Undyne, her eyes sparking. "I certainly think you need to come again. Don't you?"

Undyne bit her lip, her eye darkening, though she still smiled through it. She nodded, unable to speak - especially when Alphys sat down in her lap and grinned at her in return.

Alphys slipped her hand down between them and touched Undyne, trailing her fingers slowly over still-slick folds. Undyne closed her eye and purred softly from deep in her throat, something that delighted Alphys.

"Mm," Alphys murmured, barely realising she was speaking aloud. "You're so wet... I wonder if I'd just end up slipping right off..."

"Mistress..." Undyne murmured, her tone one of pleading. She bared her teeth for a moment, pulling on her restraints hard in her hope to bring Alphys closer. "Mistress...!"

Alphys pulled her hand away and smiled, licking her fingers slowly with her eyebrows raised. Undyne opened her eye and watched her, her breath catching for a moment, before she started to pull harder.

 _"Alphy!"_ she begged, her voice cracking.

"Yes, Undyne?" Alphys replied cheerfully, sliding her arms around Undyne's waist and pushing herself close, pressing against Undyne as much as she could.

Undyne squirmed, her face bright red and her mouth dry. "Mistress, please?!" she repeated, her eye searching Alphys's, seeing a kind of triumphant lust there that made her desperate. "Please, _please, just fuck me?!"_

Alphys grinned, her eyes dancing, and she nodded. However, she made a point to move as slowly as possible, adjusting her legs to tangle with Undyne's and reaching down briefly to make sure they were as close as possible.

"Okay," she whispered into Undyne's ear, making her shiver and swallow a groan.

When she finally pushed close so that their skin touched, Undyne gasped out, shutting her eye tight and pulling very hard on the restraints. They held her firmly in place, though they didn't hurt her or dig into her skin, like she thought they would. She pushed her hips up against Alphys's, meeting her next thrust, and Alphys was the one who made a sound, that time.

Alphys tangled her hands into Undyne's hair, lifting her head up to kiss her - something that had Undyne purring in relief. Alphys kept the pace slow, making sure every single shift of her hips was met by Undyne's, and she smiled, her eyes fluttering closed and her tail reaching out to hook around one of Undyne's shins.

Undyne pressed her forehead to Alphys's, breaking from the kiss to whisper her name, her eye still shut tight. She was panting, a mess of sweat and need, she knew, but she couldn't help it.

This was a kind of sweet torture that begged her to abandon herself to it, so she did.

She felt incredible, control completely gone from her reach and held firmly by Alphys, and she found herself thrilled by this, as she trusted Alphys with her very life, and knew that Alphys would _never_ abuse this trust.

When Alphys kissed her again, she returned it fiercely, a wave of sudden tenderness for her wife filling her.

Alphys was in a similar state. A year ago, this kind of thing would have been rather alien, a thing that probably would never of happened if Alphys hadn't bought that collar.

On that thought, she reached down and hooked her index finger through the look of that collar, pulling on it a little, and she felt Undyne shudder against her, a small moan escaping between their lips. Alphys had never know that she had this side to her personality, but she truly enjoyed it - especially when seeing how much Undyne enjoyed it, too.

"Mistress," Undyne growled out, reminding her of that fact rather quickly. "I... I'm _close_..."

It was true; it hadn't taken long, her body still sensitive from her previous orgasm, but she didn't care.

Alphys smiled. _"Good,"_ she replied, pushing closer and increasing the pace, bringing out a sharp cry from Undyne, who met each move with an eagerness that surprised her - but not enough to stop.

 _"Yes..."_ Undyne suddenly murmured, throwing her head back against the headboard, her teeth bared. "Mistress...! I... _I'm...!"_

Alphys cut her off, kissing her so hard she groaned, and in that moment, she felt her control break, and she fell into it, her orgasm crashing through her so hard she trembled. Alphys kept kissing her through it, tugging gently on the collar - something that had Undyne whispering her name breathlessly against her lips.

Undyne then relaxed beneath Alphys, practically melting from bliss. She laughed hoarsely, licking her lips. She felt _amazing_ , like nothing could ever hurt her ever again...

"Alphy..." she murmured, leaning forward to nuzzle her neck gently. She felt Alphys shiver - as well as pull a little on the collar - and her eye opened, a smile playing upon her lips.

Alphys stared back at her, and with a raise of an eyebrow, Undyne shifted her hips up, and Alphys gasped, clinging onto her tight.

"Hm," Undyne said, her voice low. "Mistress, I'd like it very much if _you_ came, now, please."

Alphys shivered again, her arms going around Undyne's neck, pushing closer to her. Undyne closed her eye, pulling on her restraints a little in a sudden urge to hold her.

"Mistress," she added. "Can I be free, to hold you?"

Alphys leaned back a little to meet her gaze, and she smiled.

"Nope," she replied, a glint of mischief in her eyes.

She kept her eyes locked with Undyne's as she started to move again, slowly, but Undyne's eye immediately closed, sighing as those gentle thrusts sent equally gentle pleasure through her.

Alphys closed her eyes, allowing her instincts to take over, and soon she increased the pace, her blood humming with pleasure as it built slowly within her. Undyne rested her cheek against hers, and she nuzzled it, something that had them both purring. They kissed, and suddenly Alphys was filled with desperation, needing _more_ than just kissing.

"Undyne," she murmured between kisses. " _Undyne_..." Her hands moved to Undyne's shoulders, her claws digging in, and she moved faster, her cries increasing.

Undyne watched her, her heart racing, as her wife started to lose control, her body becoming almost clumsy in her eagerness.

"Come for me, Mistress," Undyne replied, unable to look away from her, now.

Alphys then clung to her, burying her face into her neck, crying out her name as she came - and _hard_ , too, something that surprised her a little.

The moment she did, however, was the moment the restraints suddenly vanished.

Undyne immediately grabbed hold of her, keeping her close, something that had her murmuring in relief and nuzzling closer to her, overcome, now.

Undyne rubbed her back, closing her eye and resting her cheek against the top of her head, still grinning. Alphys laughed a little, and Undyne hugged her tighter, turning it into giggles, instead.

"W-well," Alphys murmured, her eyes closed, listening to Undyne's heartbeat. "Th-that was... _amazing."_

Undyne laughed, unable to help it: Alphys's tone was surprised. "You're a _very_ good mistress, Alphy," Undyne reminded her.

Alphys buried her face closer, blushing. "It was... okay?"

" _More_ than okay!" Undyne insisted. "It would have been over the second I fucked up if you hadn't thought of magic!  _Duh_. Why didn't _I_ think of that?!"

Alphys giggled. "The blood from your brain was elsewhere."

Undyne laughed again, this time without pause, and Alphys joined her.

It wouldn't be the last time, of course. But it was an incredibly nice start.

**\--THE END--**


End file.
